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The next round of talks between Iran and world powers is scheduled for this week in Geneva

Iran's Supreme Leader Ayatollah Ali Khamenei said Sunday that he supports his nation's nuclear negotiations with world powers, but he is not so "optimistic" about the talks.

He made the remarks while addressing university students, the state-run Islamic Republic News Agency reported.

"I am not optimistic about these talks but, with God's blessings, we shall not lose anything in these talks either," he said. "This experience will enhance our nation's mental capacity. If the talks succeed, so much the better. And if they don't, that should mean that the country is standing on its own feet. We should not trust an enemy who keeps smiling and says it is willing to talk but at the same time tells us 'all options are on the table.'"

Talks resumed last month between Iran and six world powers -- the United States, Russia, China, France, Germany and Britain -- known as the P5+1.

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Iran, whose economy is suffering severely under the U.S. and U.N. sanctions imposed because of its nuclear program, has long maintained that it is developing nuclear energy capabilities for peaceful purposes only.

The next round of talks between Iran and the P5+1 is scheduled for this week in Geneva.